Benthic habitats support a wide variety of marine life, from corals and fish to clams, plants, and bacteria. The organisms in benthic habitats play important roles in ecosystem health by functioning as part of the ocean food web and helping to filter pollutants out of the water. Healthy habitats also play an important economic role by providing food, protecting areas from erosion, and sustaining tourism-related jobs. To map these habitats and assess how they are changing, NOS uses satellite and airborne sensors, acoustic imaging, photography, and benthic community analysis. Aerial photographs are also used to create maps of coral reefs and other habitats. And the Coastal and Marine Ecological Classification Standard provides a unifying framework allowing assessment of habitats on both a local and regional basis.